Water Monitoring

Tracking Levels of Radiation Linked to the Tsunami and Nuclear Power Event in Japan

The Oregon Public Health Division and the Environmental Protection Agency continue to track levels of radiation linked to the tsunami and nuclear power plant event in Japan. There is no public health risk due to the trace levels of radiation from Japan.

Sampling Program

Even before the 2011 Japan Event occurred, the Oregon Public Health Division has had an ongoing environmental sampling program in place. Radiation Protection Services (RPS) evaluates water at a standard environmental sampling frequency. Rain water is collected continually and shipped to the EPA for analysis. Drinking water is collected and analyzed quarterly.

These analyses continually show normal background levels of radiation. According to the U.S. Environmental Protection Agency, the radiation levels would have to be hundreds of thousands of times higher before Oregonians need to take any protective actions.

Sampling Timelines

Beginning in April 2012, in light of the potential landfall of Japan Tsunami marine debris along the Oregon coast, OPH and RPS began enhanced sampling activity of surf water, sand from the high tide line and drinking water from three locations along the Oregon coast.

In March 2013, RPS performed a scientific review that included 12 months worth of data obtained from the coastal sample analyses. The results of the review show that it is highly unlikely that Japan tsunami marine debris presents a radiation public health risk.

Based on the review of the data collected to date, effective April 2013, RPS has changed it sampling protocol to quarterly. RPS will continue to work with the Beach Rangers and the Department of Parks and Recreation to collect samples and will continue to post the results on our website. If RPS does identify an increase of activity from any of the collected samples, it will increase the sampling frequency to ensure the safety of our beaches and the health of the citizens of the state of Oregon.

On May 1, 2017, RPS performed its second review of the scientific data collected since the inception of the beach monitoring program in April, 2012. Based on the results collected to date, there is no scientific evidence that Japan Tsunami marine debris presents a radiation health concern. As such, RPS is changing the sampling protocol from quarterly to semi-annually. Working in cooperation with the Department of Parks and Recreation's Beach Rangers program, RPS will collect samples of ocean water, sand from the high tide line, and drinking water in May and November. The results of the sample analysis will be published on the RPS web page as they become available. In the event that RPS does detect an increase of activity from any of the collected samples, it will revert back to a more frequent sampling schedule.

Sampling Data - Gamma Spectroscopy Analysis

Drinking Water

The following data was obtained from drinking water samples that were collected in Portland and at various locations along the Oregon Coast. Samples are collected quarterly and are analyzed for cesium-137 and iodine-131 content. Data is updated on the website quarterly.

*Minimum Detectable Activity (MDA): The MDA is defined as the smallest quantity of radioactivity that can be distinguished from background radiation under specified conditions.

Units: Picocurie (pCi): A unit of measurement that tells you the rate at which a sample of radioactive material decays.>1 pCi=0.037 Becquerel (Bq) = 2.22 disintegrations/minute.

Rain Water

Rain water samples are collected in Portland on a continual basis and shipped to the EPA for further analysis. The analysis performed there can detect increases in radiation levels that would identify a potential threat to the public's health. Detailed test results by location can be seen on the EPA website.

For a period of time after the Japanese nuclear reactors were damaged, RPS analyzed the rain samples collected in Portland, OR for gamma emitting radionuclides prior to shipping the samples to the EPA. The results from the analyses were periodically posted to the website. The results have continuously shown no elevated readings since May of 2011.As a result, RPS has chosen to discontinue posting these results. Historical results obtained by RPS are listed below.

The following data was obtained from sea water samples that were collected from various locations along the Oregon Coast. Samples are collected quarterly and are analyzed for cesium-137 and iodine-131 content. Data is updated on the website quarterly.